I'm sympathetic to your concern about the use of the word "literally". It's sort of a special, meta word. But there's a subtle difference here in how they used

I'm sympathetic to your concern about the use of the word "literally". It's sort of a special, meta word. But there's a subtle difference here in how they used it. They said "even if the UX is ... 'the software literally shoots knives'". They're speaking in hyperbole, not metaphor. So "literal" is somewhat appropriate. They're not directly saying that their boss wouldn't care about a bad UI. They're exaggeratedly saying that their boss wouldn't care about literal injury.